I got an interesting question today about how long it will take a firm to start working with SharePoint. The answer is that you can start a Proof of Concept very quickly. A stand alone installation of SharePoint on a Virtual PC 2007 Virtual Image can be made in about a day. Once it is created you can start developing out of the features from the very start of a requirements workshop.
I will always start a project with a SharePoint virtual image. In this way you can show the stakeholders how the site can function and get them to start thinking about using the out of the box features rather than develop time consuming solutions.
As you refine the requirements you can have a SharePoint farm for UAT and Live built at the same time. You will almost always want to deploy SharePoint with 2 Web Front End, an Application Server and a Active-Passive Database cluster. This is a minimal redundent secured solution. Because of the number of servers involved virtual VMWare ESX should be used for most servers.
You can develop using Virtual PC as the farm is created and tested. It should never take more than 3 weeks to create, test and fully harden a SharePoint farm back end. If someone takes 3 months to just install it out of the box there is something wrong.
Then when the UAT environment is built you can use stsadm.exe to make a backup and restore to move the work you have done to the UAT or Live environments.